I will chime in with my thoughts.

I run a business that needs to send lots of money to Colombia.

1. I do not know of any way to credit Nequi and Daviplata from an overseas account. There's a Rappi card available through the app. There might be a convoluted way of topping that up with a foreign card but you mention the bank account was closed down and I think it is necessary to tie these virtual payment methods to a Colombian account for withdrawals

2. I disagree that bank charges are high. If I have a peso value and I am sending in USD I add 2.4% to the COP value before converting. That is my benchmark for Bancolombia but I have been noticing lately that it's nearer 2%. Davivienda is the best, it is always 1%, although they have unhelpfully blocked transfers from my bank.

3. I appreciate that all Colombian payment platforms are utter trash and often don't accept foreign cards. They frustratingly tell you that you need to contact your bank but the truth is they simply haven't bothered to request payment. Presencial transactions work though so if you can find a way to send your family a debit card then they can use it locally, and of course pull cash out of an ATM. Our company sends cards to colleagues based in Colombia and it makes things much simpler.

4. I too have bought spare pesos from people in the past. This is becoming a bit more difficult because Colombia is becoming a lot more "electronic" and people no longer tend to have a few million pesos sitting around.

5. No one has mentioned it here but there are crypto ATMs popping up all over Colombia. I am sure they also charge a % and I have no idea how they work but that's maybe also a possibility.